Incidence of Attention Deficit Hyperactivity Disorder (ADHD) Diagnoses in Navarre (Spain) from 2003 to 2019.

Leire Leache,Marta Gutiérrez-Valencia,Julián Librero,Juan Erviti,Olast Arrizibita,Luis Carlos Saiz

doi:10.3390/ijerph18179208

Abstract

(1) Background: Attention deficit hyperactivity disorder (ADHD) constitutes one of the leading mental health and behavioral disorders in childhood and adolescence. The main objective of this study was to analyze the time trend in the incidence of ADHD diagnoses in Navarre (Spain) from 2003 to 2019 in children and adolescents from 5 to 19 years old. Additionally, the seasonal trends of ADHD incidence and ADHD prevalence were determined. (2) Methods: A population-based observational retrospective study, which included people born between 1991 and 2011 and who attended compulsory education between 2007 and 2017 in Navarre (Spain), was carried out with data from both the Education and Health Department databases. (3) Results: The incidence rate increased from 4.18 cases per 1000 person-years in 2003 to 7.43 cases per 1000 person-years in 2009, before decreasing progressively to 2.1 cases per 1000 person-years in 2019. A peak incidence rate at 7–8 years of age was observed, which is consistent across the study period and for both genders. Males were more than twice as likely to be diagnosed with ADHD than females, with similar time trends in both. A seasonal pattern in ADHD diagnosis was found, with peaks in February–March and the lowest rates in the summer months. Inattentive cases were much more frequent than hyperactive cases, whereas combined cases remained low across the study period. (4) Conclusions: In this age-period-cohort analysis, a clear period and age effect was observed. We found a decreasing trend in the ADHD incidence rate since 2015. Further research is needed to confirm whether a change of trend is occurring globally.

Highlights

Attention deficit hyperactivity disorder (ADHD) constitutes one of the leading mental health and behavioral disorders in childhood and adolescence
The incidence rate was significantly higher in males than in females for most of the age range and analyzed years, except in some upper extreme ages in which significant differences were not observed; this was probably due to the lower number of participants in these age ranges
Throughout the study period, the highest incidence rate occurred in children aged

Summary

Introduction

Attention deficit hyperactivity disorder (ADHD) constitutes one of the leading mental health and behavioral disorders in childhood and adolescence. Association’s Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines ADHD in children younger than age 17 years as the presence of six or more symptoms in either the inattentive or hyperactive and impulsive domains, or both [1]. The diagnosis is mainly based on clinical signs and symptoms, as there is no sound evidence for specific analytical alterations. Even with clear-cut diagnostic criteria, there is a potential risk of overdiagnosis and underdiagnosis [2]. ADHD shows a marked heterogeneity at clinical, aetiological, and pathophysiological levels [2]. The likelihood of being diagnosed with ADHD has been associated with multiple

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